Programmable seat back damper assembly for seats

ABSTRACT

A programmable seat back damper assembly for a motor vehicle includes a generally horizontal seat cushion portion and a generally upright back portion operatively connected to the seat cushion portion. The programmable seat back damper assembly includes a recliner for operative connection to the seat back portion and the seat cushion portion. The programmable seat back damper assembly also includes a damper for operative connection to the seat back portion and the seat cushion portion and having a magneto-rheological (MR) fluid therein. The programmable seat back damper assembly further includes a controller electrically connected to the damper to control an apparent viscosity of the MR fluid to increase and decrease damping of the damper for adjusting an angle of the seat back portion relative to the seat cushion portion.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This is a divisional of application Ser. No. 09/346,380, filed Jul. 1,1999, now U.S. Pat. No. 6,312,049.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to seats for motor vehicles and,more specifically, to a programmable seat back damper assembly for aseat in a motor vehicle.

2. Description of the Related Art

It is known to provide seats for motor vehicles such as an automotivevehicle. Typically, a seat includes a generally horizontal seat cushionportion and a generally vertical seat back portion operatively connectedto the seat cushion portion. The seat may include at least one,preferably a pair of tracks to allow longitudinal adjustment of the seatcushion portion. The seat may include a recliner for reclining the seatback portion relative to the seat cushion portion by an occupant in theseat.

It is known to provide an energy absorber or damper for a seat backportion of a seat in a motor vehicle. An example of such a damper isdisclosed in U.S. Pat. No. 5,722,722. In this patent, a damper andrecliner are connected in a substantially parallel relationship withrespect to each other and secured to the seat back portion and seattrack. The recliner is configured to be disengageable in a high-energyimpact, thereby allowing the damper to dissipate energy as the seat backportion pivots with respect to the seat track.

One disadvantage of the above damper is that it is not programmable toprovide damping characteristics based on impact event characteristics.Another disadvantage is that the above damper does not allow limitedrotation of the seat back portion. A further disadvantage is that theabove damper and release mechanism includes a squib release mechanism,which is an explosive device that is not resettable for multiple uses.

SUMMARY OF THE INVENTION

Accordingly, the present invention is a programmable seat back damperassembly for a seat in a motor vehicle including a generally horizontalseat cushion portion operatively connected to vehicle structure and agenerally upright seat back portion operatively connected to the seatcushion portion. The programmable seat back damper assembly includes arecliner for operative connection to the seat back portion and the seatcushion portion. The programmable seat back damper assembly alsoincludes a damper for operative connection to the seat back portion andthe seat cushion portion and having a magneto-rheological (MR) fluidtherein. The programmable seat back damper assembly further includes acontroller electrically connected to the damper to control an apparentviscosity of the MR fluid to increase and decrease damping of the damperfor adjusting an angle of the seat back portion relative to the seatcushion portion.

One advantage of the present invention is that an improved programmableseat back damper assembly is provided for a seat in a motor vehicle.Another advantage of the present invention is that the programmable seatback damper assembly uses a magneto-rheological fluid damper todissipate energy for a seat back of a vehicle seat. Yet anotheradvantage of the present invention is that the programmable seat backdamper assembly reduces occupant kinetic energy during an impact on thevehicle through programmed and limited seat back rotation. Still anotheradvantage of the present invention is that the programmable seat backdamper assembly can be programmed to provide a dampening profile basedon impact event characteristics. A further advantage of the presentinvention is that the programmable seat back damper is resettable anduseable.

Other features and advantages of the present invention will be readilyappreciated, as the same becomes better understood, after reading thesubsequent description when taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a side elevational view of a programmable seat back damperassembly, according to the present invention, illustrated in operationalrelationship with a seat.

FIG. 1B is a fragmentary view of a portion of the programmable seat backdamper assembly of FIG. 1A.

FIG. 2A is a side elevational view of another embodiment, according tothe present invention, of the programmable seat back damper assembly ofFIG. 1A.

FIG. 2B is a fragmentary view of a portion of the seat back damperassembly of FIG. 2A.

FIG. 3 is a schematic view of yet another embodiment, according to thepresent invention, of the programmable seat back damper assembly of FIG.1A.

FIG. 4 is a schematic view of still another embodiment, according to thepresent invention, of the programmable seat back damper assembly of FIG.1A.

FIG. 5 is a schematic view of a further embodiment, according to thepresent invention, of the programmable seat back damper assembly of FIG.1A.

FIG. 6 is a schematic diagram of a control system for the programmableseat back damper assembly of FIGS. 1A through 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring now to the drawings and in particular FIG. 1A and 1B, oneembodiment of a programmable seat back damper assembly 10, according tothe present invention, is shown for a seat, generally indicated at 12,of a motor vehicle (not shown). The seat 12 includes a generallyhorizontal seat cushion portion or seat cushion 14 and a generallyupright seat back portion or seat back 16 pivotally connected to theseat cushion 14 by a seat back pivot 17. The seat cushion 14 includes aseat pan (not shown) and a cushion 18 operatively connected to the seatpan by suitable means such as an adhesive. The seat back 16 includes aseat back frame (not shown) and a cushion 20 disposed about andoperatively connected to the seat back frame by suitable means such asan adhesive. The seat 12 includes a track or lower seat frame member 22mounted to the seat pan and vehicle structure 24 such as a floorpan. Itshould be appreciated that, except for the programmable seat back damperassembly 10, the seat 12 is conventional and known in the art.

As illustrated in FIG. 1A, the programmable seat back damper assembly 10includes a recliner mechanism 26 interconnecting the seat back 16 andseat cushion 14. The recliner mechanism 26 is of a linear type asdisclosed in U.S. Pat. No. 5,568,843 to Porter et al., the disclosure ofwhich is hereby incorporated by reference. The recliner mechanism 26 hasone end connected to the seat back frame and another end connected to agrounded location such as a track or lower seat frame member 22 orvehicle structure 24 to prevent free spinning of the seat back 16 aboutthe pivot point 17. It should be appreciated that the recliner mechanism26 is similar to that disclosed in U.S. Pat. No. 5,722,722 to Massara,the disclosure of which is hereby incorporated by reference. It shouldbe appreciated that the seat back 16 pivots or reclines relative to theseat cushion 14.

As illustrated in FIGS. 1A and 1B, the programmable seat back damperassembly 10 includes a damper 28 interconnecting the seat back 16 andseat cushion 14. In this embodiment, the damper 28 is of a linear type.The damper 28 includes a housing 30 having a generally cylindrical shapewith a cavity 32 therein. The housing 30 may incorporate a flexiblediaphragm or floating piston 31 forming another cavity 33 that ispressurized to act as an accumulator for a fluid to be described. Thehousing 30 is made of a ferrous material. The housing 30 has one end 34attached by suitable means (not shown) to either the track or lower seatframe member 22 or vehicle structure 24.

The damper 28 includes a piston 36 disposed within the cavity 32 of thehousing 30 and movable therein. The piston 36 has a generallycylindrical shape with a generally circular cross-section. The piston 36is made of a ferrous material. The piston 36 extends axially and has anannular groove or recess 38 circumferentially thereabout for a functionto be described.

The damper 28 also includes a piston rod 40 disposed partially in thecavity 32 of the housing 30 and connected to the piston 36. The pistonrod 40 has a generally cylindrical shape and has a generally circularcross-section. The piston rod 40 has one end connected to the piston 36and extends axially through an aperture 42 in another end of the housing30 and has another end connected to the seat back 16. A seal (not shown)is disposed about the piston rod 40 in the aperture 42 in the end of thehousing 30. The piston rod 40 is made of a ferrous material. It shouldbe appreciated that the piston rod 40 is hollow for a function to bedescribed.

The damper 28 also includes a coil 44 disposed within the cavity 32 ofthe housing 30 and about the piston 36. The coil 44 is generally annularand disposed in the groove 38 of the piston 36. The coil 44 is spaced apredetermined distance from the housing 30. The coil 44 is connected bysuitable means such as wires 46 to a source of power such as acontroller 50 to be described.

The damper 28 further includes a magneto-rheological (MR) fluid 48disposed in the cavity 32 of the housing 30 between the piston 36, thecoil 44, and the housing 30. The MR fluid 48 contains magnetizableparticles such as carbonyl iron spheroids of about one (1) to ten (10)microns in diameter dispersed in a viscous fluid such as silicone oilwhich has a viscosity of between about 20 and 50,000 mPa. It should beappreciated that the MR fluid 48 may also contain surfactants, flowmodifiers, lubricants, viscosity enhancers, and other additives. Itshould also be appreciated that the MR fluid 48 is conventional andknown in the art.

The programmable seat back damper assembly 10 includes a controller 50such as a restraint control module connected by the wires 46 to the coil44. The wires 46 extend from the controller 50 through the piston rod 40to the coil 44. The controller 50 is programmable to send various amountof current to the damper 28. The damping force of the MR fluid 48 isprogrammed by the controller 50 based on various factors such as mass,stature, location and possibly age of an occupant (not shown) and theinertia sensed. It should be appreciated that the amount of dampeningprovided is controllable and changeable during its operation dependingupon the above factors.

The programmable seat back damper assembly 10 includes an inertia sensor52 connected to the controller 50. The inertia sensor 52 sends a signalto the controller 50 of the amount of inertia sensed. It should beappreciated that the controller 50 and inertia sensor 52 areconventional and known in the art.

In operation of the programmable seat back damper assembly 10, duringnormal operating conditions, the recliner 26 operates as a conventionalrecliner to control the adjustment of the seat back 16 relative to theseat base 14. The recliner 26 is unlocked to allow adjustment and thenlocked to hold the chosen position. During this normal operation, thedamper 28 is inactive and the piston 36 moves relative to the housing 30as required to accommodate the position adjustment. When an impactcollision condition occurs as sensed by the inertia sensor 52, a signalis sent to the controller 50. The controller 50 sends a signal to anactuator such as a solenoid (not shown) located on a housing (not shown)of the recliner 26 to disengage the recliner 26 and sends a signalsimultaneously to the damper 28 to pass a current through the coil 44 togenerate a magnetic field. The magnetic field increases the apparentviscosity of the MR fluid 48 and thus increases the damping forcegenerated by the damper 28. The increased viscosity of the MR fluid 48dissipates energy by allowing the seat back 16 to rotate about its pivotpoint and permits some highly damped occupants eat back rotation duringthe impact, thus reducing the kinetic energy of the occupant. Whenenergy dissipation is completed, the controller 50 sends a signal to theactuator to re-engage the recliner 26 and deactivates the damper 28. Itshould be appreciated that the amount of current passed through the coil44 is programmable by the controller 50, thus affecting the strength ofthe magnetic field and viscosity of the MR fluid 48. It should also beappreciated that the recliner 26 carries the load of the seat back 16during normal driving condition, is disengaged when the damper 28 is todissipate energy, and is re-engaged when the energy dissipation iscompleted. It should further also be appreciated that the programmableseat back damper assembly 10 is used on both sides of the seat 12.

Referring to FIGS. 2A and 2B, another embodiment 110, according to thepresent invention, of the programmable seat back damper assembly 10 isshown. Like parts of the programmable seat back damper assembly 10 havelike reference numerals increased by one hundred (100). The programmableseat back damper assembly 110 includes a damper 128 of the rotary type.The damper 128 is attached to and disposed about a shaft 153 of the seatback pivot 17. The damper 128 includes a housing 130 disposed about andspaced radially from the shaft 153 of the seat back pivot 17. Thehousing 130 has a cavity 132 with axial open ends 154 to form agenerally “C” shaped cross-section at each end. The housing 130 is madeof a ferrous material. The recliner 26 is attached by suitable means(not shown) to the shaft 153 and the seat back support such as the frameof the seat back 16.

The damper 128 includes a bearing 156 disposed about the shaft 153 andin each open end 154 of the housing 130. The bearing 156 is of a sealedroller type to allow rotation of the shaft 153 relative to the housing130.

The damper 128 also includes a driven member 158 disposed within thecavity 132 of the housing 130 and about the shaft 153. The driven member158 is generally circular in shape. The driven member 158 may be one ormore discs. The discs are alternated between rotatable discs fixed tothe shaft 153 and stationary discs fixed to the housing 130. The drivenmember 158 is made of a ferrous material. The driven member 158 is fixedto the shaft 153 by suitable means such as a key (not shown).

The damper 128 also includes a coil 144 disposed within the cavity 132of the housing 130 and about the driven member 158. The coil 144 isspaced a predetermined distance from the driven member 158. The coil 144is connected by suitable means such as wires 146 to a source of powersuch as the controller 50.

The damper 128 further includes a magneto-rheological (MR) fluid 148disposed in the cavity 132 of the housing 130 between the driven member158, the coil 144, and the bearings 156. The operation of theprogrammable seat back damper assembly 110 is similar to theprogrammable seat back damper assembly 10.

Referring to FIG. 3, another embodiment 210, according to the presentinvention, of the programmable seat back damper assembly 10 is shown.Like parts of the programmable seat back damper assembly 10 have likereference numerals increased by two hundred (200). In this embodiment,the damper 228 and recliner 226 are arranged in series between the seatback 16 and seat cushion 14. The damper 228 and recliner 226 of theprogrammable seat back damper assembly 210 are of the linear type. Thedamper 228 has a housing 230, piston 236, and piston rod 240. Therecliner 226 has a housing 260 and a rod 262 extending through thehousing 260. The housing 230 has one end connected to the tracks orlower seat frame member 22 of the seat 12 or vehicle structure 24 suchthat it is mechanically grounded. The piston rod 240 has one endconnected to the piston 236 and another end connected to the rod 262 ofthe recliner 226. The rod 262 of the recliner 226 is operativelyconnected to the frame of the seat back 16 by a link 264 such that theseat back 16 pivots about the seat back pivot 17. In this embodiment,the piston rod 240 and recliner rod 262 are a single rod. Similarly, thehousing 230 and housing 260 are a single housing. The operation of theprogrammable seat back damper assembly 210 is similar to theprogrammable seat back damper assembly 10.

Referring to FIG. 4, another embodiment 310, according to the presentinvention, of the programmable seat back damper assembly 10 is shown.Like parts of the programmable seat back damper assembly 10 have likereference numerals increased by three hundred (300). In this embodiment,the damper 328 and recliner 326 of the programmable seat back damperassembly 310 are of the linear type. The damper 328 has a housing 330,piston 336, and piston rod 340. The recliner 326 has a housing 360 and arod 362 extending through the housing 360. The housing 330 has one endconnected to the tracks or lower seat frame member 22 of the seat 12 orvehicle structure 24 such that it is mechanically grounded. The pistonrod 340 has one end connected to the piston 336 and another endconnected to the rod 362 of the recliner 326. The rod 362 of therecliner 326 is operatively connected to the frame of the seat back 16by a link 364 such that the seat back 16 pivots about the seat backpivot 17. In this embodiment, the piston rod 340 and recliner rod 362are a single rod. The housing 330 and housing 360 are two separatehousings. The programmable seat back damper assembly 310 also includes abracket 366 connected to the housing 360 of the recliner 326 and thetracks or lower seat frame member 22 of the seat 12 such that it ismechanically grounded. The bracket 366 allows the recliner housing 360to rotate about the damper pivot point and restrains movement of therecliner housing 360 relative to the rod axial direction. The bracket366 has a slot 367 allows this motion. As the seat back 16 rotates, therecliner housing 360 moves upward in an arc motion. The operation of theprogrammable seat back damper assembly 310 is similar to theprogrammable seat back damper assembly 10.

Referring to FIG. 5, another embodiment 410, according to the presentinvention, of the programmable seat back damper assembly 10 is shown.Like parts of the programmable seat back damper assembly 10 have likereference numerals increased by four hundred (400). In this embodiment,the damper 428 and recliner 426 are arranged in parallel between theseat back 16 and seat cushion 14. The damper 428 and recliner 426 of theprogrammable seat back damper assembly 410 are of the linear type. Thedamper 428 has a housing 430, piston 436, and piston rod 440. Therecliner 426 has a housing 460 and a rod 462. The housing 430 has oneend connected to the tracks or lower seat frame member 22 of the seat 12or vehicle structure 24 such that it is mechanically grounded. Thehousing 460 has one end connected to the tracks or lower seat framemember 22 of the seat 12 or vehicle structure 24 such that it ismechanically grounded. The piston rod 440, has one end connected to thepiston 436 and another end connected to the rod 462 of the recliner 426.The rods 440 and 462 are operatively connected to the frame of the seatback 16 by a link 464 such that the seat back 16 pivots about the seatback pivot 17. In this embodiment, the piston rod 440 and recliner rod462 are two separate rods. Similarly, the housing 430 and housing 460are two separate housings. The operation of the programmable seat backdamper assembly 410 is similar to the programmable seat back damperassembly 10.

Referring to FIG. 6, a control system 500, according to the presentinvention, is shown for the programmable seat back damper assembly10,110,210,310,410. The control system 500 may include a centralprocessing unit (CPU) 502 interconnecting the controller 50 and theinertia sensor 52. In this embodiment, the CPU 502 is optional and usedto gather data and make a control profile for the controller 50 toexecute. The control system 500 may also include at least one,preferably a plurality of sensors such as an occupant weight sensor 504,occupant stature sensor 506 and other occupant profile sensors 508connected to the CPU 502. The sensors 504, 506 and 508 may be mounted inthe seat 14 or a roof rail (not shown) or headliner (not shown) of themotor vehicle to provide information about the occupant seated in theseat 12. The control system 500 also includes the controller 50connected to the CPU 502 and to the damper 28,128,228,328,428 of theprogrammable seat back damper assembly 10,110,210,310,410. The damper28,128,228,328,428 is operatively connected to the seat back 16 orrecliner 26,126,226,326,426. The control system 500 may also obtainoccupant information that is inputted by the occupant and stored inmemory of the CPU 502 or obtained by a computer system that caninterrogate occupants about their height, weight, etc.

The control system 500 may further includes a recliner sensor 510interconnecting the recliner and the CPU 502. The recliner sensor 510acts as a back-up redundant sensor to cooperate with the inertia sensor52 to ensure proper performance of the control system 500. The reclinersensor 510 may be located in the recliner mechanism 26,226,326,426 forthe seat 12. It should be appreciated that the recliner sensor 510provides an indication of the amount of reclining of the seat back 16relative to the seat cushion 14. It should also be appreciated that therecliner sensor 510 is conventional and known in the art.

In operation of the control system 500, the sensors 504,506,508 providesignals to the CPU 502 regarding the occupant. Upon an impact on themotor vehicle, the inertia sensor 52 provides a signal to the CPU 502 ofvehicle impact conditions. The CPU 502 provides a signal to thecontroller 50 that controls the damper 28,128,228,328,428, in turn,controlling the angular adjustment of the seat back 16 relative to theseat cushion 14. The recliner sensor 510 provides a signal to the CPU502 of the amount reclining of the seat back 16 relative to the seatcushion 14, which is then communicated to the controller 50 to controlthe damper 28,128,228,328,428.

The present invention has been described in an illustrative manner. Itis to be understood that the terminology, which has been used, isintended to be in the nature of words of description rather than oflimitation.

Many modifications and variations of the present invention are possiblein light of the above teachings. Therefore, within the scope of theappended claims, the present invention may be practiced other than asspecifically described.

What is claimed is:
 1. A programmable seat back damper assembly for aseat in a motor vehicle comprising: a damper for operative connection toeither one of a seat back portion, a recliner, and a seat cushionportion of the seat, said damper including a housing having a cavity anda magneto-rheological (MR) fluid disposed in said cavity; and acontroller electrically connected to said damper and being programmablebased on predetermined factors to send a signal thereto to generate amagnetic field to increase an apparent viscosity of the MR fluid toincrease damping of said damper during an impact collision conditionbased on the predetermined factors, wherein in an impact on the motorvehicle, said damper dissipates energy as the seat back portion rotatesrelative to the seat cushion portion.
 2. The programmable seat backdamper assembly as set forth in claim 1 wherein said damper is a lineardamper.
 3. A programmable seat back damper assembly for a seat in amotor vehicle having a generally horizontal seat cushion portion and agenerally upright seat back portion operatively connected to the seatportion, said programmable seat back damper assembly comprising: arecliner for operative connection to the seat back portion and the seatportion of the seat; and a damper for operative connection to either oneof the seat back portion, said recliner, and the seat cushion portionand having a magneto-rheological (MR) fluid therein; and a controllerelectrically connected to said damper and being programmable based onpredetermined factors to send a signal thereto to generate a magneticfield to increase an apparent viscosity of the MR fluid to increasedamping of said damper during an impact collision condition based on thepredetermined factors, wherein in an impact on the motor vehicle, saiddamper dissipates energy as the seat back portion rotates relative tothe seat cushion portion; and wherein said damper includes a housinghaving a cavity, said MR fluid being disposed in said cavity.
 4. Theprogrammable seat back damper assembly as set forth in claim 3 whereinsaid damper includes a coil disposed in said cavity and electricallyconnected to said controller.
 5. The programmable seat back damperassembly as set forth in claim 4 wherein said damper includes a pistonbeing disposed in said cavity and movable therein.
 6. The programmableseat back damper assembly as set forth in claim 1 including an inertiasensor electrically connected to said controller to sense inertia of themotor vehicle.
 7. The programmable seat back damper assembly as setforth in claim 1 including at least one occupant sensor electricallyconnected to said controller to sense a profile of an occupant seated inthe seat of the motor vehicle.
 8. A programmable seat back damperassembly as set forth in claim 1 wherein said recliner and said damperare arranged in series between the seat back portion and the seatcushion portion.
 9. A programmable seat back damper assembly for a seatin a motor vehicle having a generally horizontal seat cushion portionand a generally upright seat back portion operatively connected to theseat portion, said programmable seat back damper assembly comprising: arecliner for operative connection to the seat back portion and the seatportion of the seat; and a linear damper for operative connection to theseat back portion and the seat cushion portion, said damper including ahousing having a cavity and a magneto-rheological (MR) fluid disposed insaid cavity; and a controller electrically connected to said damper tocontrol an apparent viscosity of the MR fluid to increase and decreasedamping of said damper for adjusting an angle of the seat back portionrelative to the seat cushion portion.
 10. A programmable seat backdamper assembly for a seat in a motor vehicle having a generallyhorizontal seat cushion portion and a generally upright seat backportion operatively connected to the seat portion, said programmableseat back damper assembly comprising: a recliner for operativeconnection to the seat back portion and the seat portion of the seat;and a damper for operative connection to the seat back portion and theseat cushion portion, said damper including a housing having a cavityand a magneto-rheological (MR) fluid disposed in said cavity, whereinsaid recliner and said damper are arranged in series between the seatback portion and the seat cushion portion; and a controller electricallyconnected to said damper to control an apparent viscosity of the MRfluid to increase and decrease damping of said damper for adjusting anangle of the seat back portion relative to the seat cushion portion.